Prepare the Cake Pans:

• Preheat the oven to 350°F (175°C).

• Grease two 9-inch round cake pans with butter or cooking spray, and line the bottoms with parchment paper for easy removal.

• Tip: Dust with flour after greasing for extra non-stick protection, and ensure pans are the same size for even layers.

Make the Cake Batter:

• In a large mixing bowl, combine 1 box vanilla cake mix, 1 cup sour cream, 3 large eggs, ½ cup vegetable oil, 1 tsp vanilla extract, and 1 cup milk.

• Beat with a hand mixer or stand mixer on medium speed until smooth and well combined, about 2 minutes, scraping the bowl as needed.

• Fold in 1½ cups crushed Oreo cookies and ¼ cup granulated sugar with a spatula until evenly distributed, about 1 minute.

• Tip: Crush Oreos in a resealable bag with a rolling pin for coarse crumbs, and avoid overmixing to keep the batter light.

Bake the Cakes:

• Divide the batter evenly between the two prepared pans, smoothing the tops with a spatula.

• Bake in the preheated oven for 25–30 minutes, or until a toothpick inserted in the center comes out clean or with a few moist crumbs.

• Let the cakes cool in the pans for 10 minutes, then transfer to a wire rack to cool completely, about 30–40 minutes.

• Tip: Rotate pans halfway through baking if your oven has hot spots, and cool fully before frosting to prevent melting.

Prepare the Oreo Frosting:

• In a medium mixing bowl, whip 2 cups heavy cream with a hand mixer or stand mixer on medium-high speed until soft peaks form, about 2–3 minutes. Set aside.

• In a large mixing bowl, beat 8 oz softened cream cheese, ½ cup powdered sugar, and 1 tsp vanilla extract on medium speed until fluffy and smooth, about 2 minutes.

• Gently fold the whipped cream into the cream cheese mixture with a spatula until fully combined, about 1 minute.

• Fold in 1 cup crushed Oreo cookies until evenly distributed, about 30 seconds.

• Tip: Chill the frosting for 10–15 minutes if it softens too much, and fold gently to maintain the whipped cream’s volume.

Assemble the Cake:

• Place one cooled cake layer on a serving platter or cake stand, flat side up.

• Spread a generous layer of Oreo frosting (about 1–1½ cups) over the top using an offset spatula.

• Place the second cake layer on top, flat side down, and press gently to secure.

• Frost the top and sides of the cake with the remaining Oreo frosting, smoothing or creating swirls as desired.

• Tip: Trim domed tops with a serrated knife for flat layers, and apply a thin crumb coat first to trap crumbs before final frosting.

Decorate (Optional):

• Melt ¼ cup white chocolate chips in a microwave-safe bowl in 15-second intervals, stirring until smooth, about 45 seconds total.

• Drizzle the melted chocolate over the top of the cake using a spoon or piping bag for a decorative effect.

• Decorate the top with 4–6 whole Oreo cookies, arranging them upright or flat, and sprinkle ¼–½ cup extra crushed Oreos around the edges or base.

• Tip: Chill the cake briefly (10 minutes) after drizzling chocolate to set it before adding Oreos, and crush extra Oreos finely for a neat sprinkle.

Chill and Serve:

• Refrigerate the cake for at least 1 hour to set the frosting and meld the flavors.

• Slice into 10–12 wedges using a sharp knife, wiping clean between cuts for neat edges.

• Serve chilled or let sit at room temperature for 15 minutes for a softer texture, optionally with extra Oreos or a scoop of vanilla ice cream.

• Tip: Run the knife under hot water for cleaner cuts, and store immediately after serving to maintain freshness.